Ten years ago, as a candidate for governor, Romney promised to “protect the right of a woman to choose,” and pledged not to change “our pro-choice laws in Massachusetts.” Three years later, after vetoing a bill that would have made it easier to get morning-after contraceptive pills, he described himself as anti-abortion and claimed his position had never changed.

Today, Romney wants the Supreme Court to repeal Roe vs. Wade, the 1973 ruling that prevents states from banning abortion, and says he would also “get rid of” Planned Parenthood, an organization he once supported.

Ryan, on the other hand, has been unswerving. The Wisconsin congressman gets a 100 percent rating from the National Right to Life Committee and zero from Planned Parenthood.

“I’m as pro-life as a person gets. You’re not going to have a truce,” he told the conservative Weekly Standard in 2010. In an essay that year, he wrote that “the right of ‘choice’ of one human being cannot trump the right to ‘life’ of another.”

Ryan has voted to ban federal funding for any health plan that covers abortion and to eliminate federal funding for Planned Parenthood. He has co-sponsored federal “personhood” legislation that would declare a fertilized embryo to be a human being, which would outlaw abortion nationwide — overriding state abortion laws — and might also affect certain types of birth control.

That goes further than Romney, who says he wants to leave the abortion issue up to the states. Romney also would allow women to terminate pregnancies caused by rape or incest, exceptions that Ryan opposes.

As for contraception, Ryan said in a recent interview that President Obama’s decision to require employers to cover birth control as part of their health insurance plans showed a “paternalistic, arrogant political philosophy” that violated “our First Amendment rights to religious freedom.”

Obama has not always championed reproductive rights. He has insisted that girls under 17 get a doctor’s prescription to obtain the “Plan B” morning-after pill, rejecting a Food and Drug Administration proposal that would have allowed them to get the pills on their own, over the counter.

He secured crucial votes from a handful of anti-abortion Democrats for his health care law by issuing an executive order that banned the use of federal funds to cover abortions in insurance sold at government-subsidized exchanges, where the uninsured can purchase coverage starting in 2014. That means women who want abortion coverage in those policies will have to buy it on their own.

But Obama’s overall policies on abortion and contraception still contrast sharply with Romney’s, and even more so with Ryan on the ticket. Nearly 40 years after the Supreme Court declared that the Constitution protects the right to terminate one’s pregnancy, and 47 years after another ruling established the right to obtain contraceptives, the future of those rights will be before the voters in November.